Sarah wants to know which brand of nail polish lasts the longest without chipping. she buys 4 types of nail polish - essie (which she normally uses,) butter, opi, and sally hanse. every sunday for 4 weeks she paints her nails with a different brand of nail polish and records how many days she lasts before she gets her first chip. she makes sure to use the same bottom coat and top coat with each types of nail polish, and she makes sure to do the same weekly routine each week so that her nails aren't getting treated more roughly
different weeks.

1. independent variable:

2. dependent variable:

3. hypothesis:

4. control group:

5. experimental group:

6. constants:

1. Independent  variable : the input variable that can be changed and controlled.
the nail polish on Sarah's nails 
2.Dependent variable: values that result from the independent variables.
days the nail polish lasts
3. Hypothesis: Different types of nail polish last different period of time without chipping.
4. Control group:the independent variable is held constant in this group and is not exposed to changes.
the time Sarah paints her nails (Sarah paints her nails every Sunday for 4 weeks)
the type of bottom coat and top coat (she uses the same bottom coat and top coat with each types of nail polish)
weekly routine (she makes sure to do the same weekly routine each week so that her nails aren't getting treated more roughly different weeks. )
Experimental group: the independent variable is changed for the experimental group 
type of nail polish (Essie, Opi and Sally Hanse)
6. Constants: the person who does the experiment (Sally), period of research (one week), her weekly routine, bottom coat and top coat,